Investigating the effect of passing retroversion heavy machinery on decreasing flood crisis relief on their pavement failure

Background and objective: Due to the fact that the desert areas of our country experience devastating floods in autumn and winter, and heavy machinery inevitably need transportation roads for relief and reconstruction in flooded areas. Pavement failure with saturated layers due to floods is considered. Method: In this research, Everstress software has been used for modeling and fine sand with 3 different moisture has been used for the subgrade soil, because the soil of desert cities is sand soil, It is more sensitive to moisture than other soils. Also, 4 types of loaders were used in modeling because this machine is mostly used in flood conditions. To investigate this issue, two parameters of maximum horizontal strain under asphalt layer and vertical strain on subgrade soil are considered. Findings: The results show that with increasing the percentage of sububgrade moisture and decreasing CBR, the values of vertical strain on the subgrade increase and the horizontal strain under the asphalt layer decrease. Found and with increasing weight loaders increase vertical strain and decrease horizontal strain. Conclusion: The use of relief equipment appropriate to the existing infrastructure is justified in order to use machines with wheel weight and less total weight should be used in passages with weaker infrastructure, because according to the results, with increasing humidity, bed soil and pavement are weakened and its load-bearing capacity is reduced, and heavy machinery traffic destroys pavement. Use of appropriate materials and strengthen the subgrade of urban thoroughfares and access to time Construction can also be a preventative measure to reduce the destructive effects of natural hazards.